Enzymatic determinations using a rotating bioreactor and continuous-flow/stopped-flow processing: Determination of glutamate in food products

Scope of study. Glutamic acid has been used as a flavoring agent in food preparations for almost a century. The use of glutamate has become controversial in the past thirty years. The purpose of this work was to develop methods that will aid the food industry to determine glutamate content in food samples. The methods use enzymes on a rotating reactor in conjunction with continuous-flow processing. Two different approaches are discussed here and both use electrochemical detection for the determination of glutamate in food samples.;Findings and conclusion. The use of the rotating reactor as a platform for the enzyme-catalyzed reaction has many advantages. The rotation of this platform decreases the Michaelis-Menten constant thereby increasing the catalytic efficiency of the reactor. Both approaches can be successfully used for the determination of food samples. Since it is a continuous flow operation several samples can be successfully analyzed in given amount of time and with the same enzyme preparation. Both systems have been successfully used for the determination of glutamate in food samples. Ascorbic acid was found to interfere in glutamate determinations with both these systems. An approach to eliminate ascorbate is also discussed in this work. Although both methods can be used for glutamate determinations, the one using the glutamate oxidase system is much more efficient. It was found to be sensitive, with lower limits of detection, and less expensive.